uspace/libc/arch/mips32/include/thread.h

   1 /*
   2  * Copyright (c) 2006 Ondrej Palkovsky
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup libcmips32
  30  * @{
  31  */
  32 /** @file
  33  * @ingroup libcmips32eb
  34  */
  35
  36 /* TLS for MIPS is described in http://www.linux-mips.org/wiki/NPTL */
  37
  38 #ifndef LIBC_mips32THREAD_H_
  39 #define LIBC_mips32THREAD_H_
  40
  41 /* I did not find any specification (neither MIPS nor PowerPC), but
  42  * as I found it
  43  * - it uses Variant II
  44  * - TCB is at Address(First TLS Block)+0x7000.
  45  * - DTV is at Address(First TLS Block)+0x8000
  46  * - What would happen if the TLS data was larger then 0x7000?
  47  * - The linker never accesses DTV directly, has the second definition any
  48  *   sense?
  49  * We will make it this way:
  50  * - TCB is at TP-0x7000-sizeof(tcb)
  51  * - No assumption about DTV etc., but it will not have a fixed address
  52  */
  53 #define MIPS_TP_OFFSET 0x7000
  54
  55 typedef struct {
  56         void *pst_data;
  57 } tcb_t;
  58
  59 static inline void __tcb_set(tcb_t *tcb)
  60 {
  61         void *tp = tcb;
  62         tp += MIPS_TP_OFFSET + sizeof(tcb_t);
  63
  64         __asm__ volatile ("add $27, %0, $0" : : "r"(tp)); /* Move tls to K1 */
  65 }
  66
  67 static inline tcb_t * __tcb_get(void)
  68 {
  69         void * retval;
  70
  71         __asm__ volatile("add %0, $27, $0" : "=r"(retval));
  72
  73         return (tcb_t *)(retval - MIPS_TP_OFFSET - sizeof(tcb_t));
  74 }
  75
  76 #endif
  77
  78 /** @}
  79  */